Portion of a keyboard



FIG. 1 is a perspective view of a portion of a keyboard showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a right side view thereof; and,

FIG. 6 is a left side view thereof.

The broken line showing of the remainder of the keyboard is for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a portion of a keyboard, as shown and described. 